May, G. C., Fitzpatrick, P A., Cullen, S. J., Kelly, L., O'Hagan, A., & Warrington, G. D. (2011). An analysis of the impact of acute sleep deprivation on repeat cycling time trial performance. Medicine and Science in Sports and Exercise, 43(5). Supplement abstract 1023.

This study evaluated the effects of acute sleep deprivation, over 24 hours, on a repeat cycling time-trial performance in trained male cyclists (N = 6). Ss were tested on three occasions all separated by seven days within a 21-day period. During the first test, Ss performed a maximal incremental test on an electromagnetically-braked cycle ergometer. Following a standardized recovery period, each S then completed a baseline 20-minute self-paced maximal performance test. Ss subsequently returned on two further occasions to perform two 24-hour trials. During the course of each 24-hour trial, Ss performed a total of four self-paced maximal performance tests at set times in either a sleep-deprived and or sleep-normal state following a randomized crossover design. The self-paced maximal performance tests were undertaken at 0, 8, 17, and 24 hours. During the sleep-deprived trial, Ss accrued no sleep, while during the sleep-normal trial they were allocated an 8-hour sleep period between 8 and 17 hours.

The sleep-normal condition resulted in a sleep duration of ~365 minutes. No significant differences were found across baseline trials for each of the three tests or for the mean cumulative distance covered over the four self-paced maximal performance tests between and within both conditions. Total distance covered decreased significantly between 8 and 17 hours in the sleep-deprived condition. No significant differences were observed across trials in the sleep-normal treatment.

Implication. Performance decreases during times when sleep habitually occurs (circadian rhythm) but over 24 hours, total performance is not compromised.

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